---
id: CVE-2026-50260
title: >-
  A use-after-free flaw was found in the X.Org X server and Xwayland in
  FreeCounter()
summary: >-
  A use-after-free flaw was found in the X.Org X server and Xwayland in
  FreeCounter(). A client that sets up multiple SyncCounters and awaits on those
  triggers can trigger a use-after-free when destroying those counters via a
  second client…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-416
  - CWE-416
vendor: x.org
product: x_server
affected:
  - x_server < 21.1.23
  - xwayland < 24.1.12
  - enterprise_linux = 7.0
  - enterprise_linux = 8.0
  - enterprise_linux = 9.0
  - enterprise_linux = 10.0
patched:
  - x_server 21.1.23
  - xwayland 24.1.12
published: '2026-06-05'
updated: '2026-07-07'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-50260'
references:
  - url: 'https://access.redhat.com/errata/RHSA-2026:26562'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:26566'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:26590'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:26610'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:26709'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:28923'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:29844'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:36086'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/security/cve/CVE-2026-50260'
    label: secalert@redhat.com
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2485385'
    label: secalert@redhat.com
  - url: >-
      https://gitlab.freedesktop.org/xorg/xserver/-/commit/f5abfb61994471023d8c6470428c8e30c411cc0b
    label: secalert@redhat.com
  - url: 'https://lists.x.org/archives/xorg-announce/2026-June/003702.html'
    label: secalert@redhat.com
  - url: 'https://redhat.atlassian.net/browse/PSIRTSUPT-16950'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:26562'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:26566'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:26590'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:26610'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:26709'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:28923'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:29844'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/security/cve/CVE-2026-50260'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2485385'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-50260.json
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
tags:
  - nvd
epss: 0.00197
epssPercentile: 0.08315
ingestedAt: '2026-07-07T08:52:24.943Z'
---

## Overview

A use-after-free flaw was found in the X.Org X server and Xwayland in FreeCounter(). A client that sets up multiple SyncCounters and awaits on those triggers can trigger a use-after-free when destroying those counters via a second client connection. This may be used to crash the server, or for privilege escalation if the X server runs as root.

## Affected

- `x_server < 21.1.23`
- `xwayland < 24.1.12`
- `enterprise_linux = 7.0`
- `enterprise_linux = 8.0`
- `enterprise_linux = 9.0`
- `enterprise_linux = 10.0`

## Remediation

Upgrade past the affected range:

- `x_server 21.1.23`
- `xwayland 24.1.12`